反应 #2507835

反应方程式

Ethyleneglycol

p-toluenesulfonic acid

5-bromopyridine-2-carbaldehyde

→

5-bromo-2-(1,3-dioxolan-2-yl)pyridine

收率 84.0%

溶剂

toluene

反应条件

后处理

1. 1
   温度at refluxing temperature
2. 2
   其他the mixture is quenched with saturated aqueous NH4Cl
3. 3
   萃取extracted with CH2Cl2
4. 4
   洗涤washed with H2O
5. 5
   萃取The aqueous layer is extracted with CH2Cl2
6. 6
   萃取the combined organic extract
7. 7
   洗涤is washed with brine
8. 8
   干燥dried over Na2SO4
9. 9
   浓缩concentrated under reduced pressure
10. 10
    其他The residue is purified by silica gel column chromatography (hexane-AcOEt (9:1 V/V))

实验过程

Ethyleneglycol (14.88 g, 0.24 mol) and p-toluenesulfonic acid (3 g, 0.16 mol) are added to a solution of 5-bromopyridine-2-carbaldehyde (30 g, 0.16 mol) in toluene (150 ml) at room temperature and the mixture is stirred for 10 hrs at refluxing temperature. After cooling to room temperature, the mixture is quenched with saturated aqueous NH4Cl, extracted with CH2Cl2 and washed with H2O. The aqueous layer is extracted with CH2Cl2 and the combined organic extract is washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (hexane-AcOEt (9:1 V/V)) to afford 5-bromo-2-(1,3-dioxolan-2-yl)pyridine (30.9 g, 84%) as a colorless oil. %). 1H NMR (400 MHz, CDCl3) δ 8.69 (s, 1H), 7.87 (m, 1H), 7.45 (m, 1H), 5.83 (s, 1H), 4.13 (m, 4H).

来源